es6 cleanup `index.js`
es6 cleanup `index.js`

ember-fastboot/ember-cli-fastboot,josemarluedke/ember-cli-fastboot,kratiahuja/ember-cli-fastboot,kratiahuja/ember-cli-fastboot,tildeio/ember-cli-fastboot,josemarluedke/ember-cli-fastboot,tildeio/ember-cli-fastboot,ember-fastboot/ember-cli-fastboot